JSString should be printable to text/javascript

[clarkevans]

Hello. So, the HTML object permits one to create objects that are HTML fragments, suitable to be displayed as "text/html".

julia> obj = HTML("<span>Hi</span>")
HTML{String}("<span>Hi</span>")
julia> display("text/html", obj)
<span>Hi</span>

The same should be true for JSString.

julia> expr = @js for i in 1:10
           console.log(i)
       end
JSString("for(var i = 1; i <= 10; i = i + 1){console.log(i)}")
julia> display("text/javascript", expr)
ERROR: MethodError: no method matching show(::Base.TTY, ::MIME{Symbol("text/javascript")}, ::JSString)

This issue can be addressed with the following:

julia> Base.show(io::IO, ::MIME"text/javascript", js::JSString) = 
           print(io, js)

julia> display("text/javascript", expr)
for(var i = 1; i <= 10; i = i + 1){console.log(i)}

Thanks.